26799a6311
The pda rework (commit 3461b0af02)
to remove static boot cpu pdas introduced a performance bug.
_boot_cpu_pda is the actual pda used by the boot cpu and is definitely
not "__read_mostly" and ended up polluting the read mostly section with
writes. This bug caused regression of about 8-10% on certain syscall
intensive workloads.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Acked-by: Mike Travis <travis@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
/*
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* prepare to run common code
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*
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* Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
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*/
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/percpu.h>
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#include <linux/start_kernel.h>
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#include <linux/io.h>
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#include <asm/processor.h>
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#include <asm/proto.h>
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#include <asm/smp.h>
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#include <asm/setup.h>
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#include <asm/desc.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/sections.h>
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#include <asm/kdebug.h>
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#include <asm/e820.h>
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#include <asm/bios_ebda.h>
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#include <asm/trampoline.h>
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/* boot cpu pda */
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static struct x8664_pda _boot_cpu_pda;
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#ifdef CONFIG_SMP
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/*
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* We install an empty cpu_pda pointer table to indicate to early users
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* (numa_set_node) that the cpu_pda pointer table for cpus other than
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* the boot cpu is not yet setup.
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*/
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static struct x8664_pda *__cpu_pda[NR_CPUS] __initdata;
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#else
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static struct x8664_pda *__cpu_pda[NR_CPUS] __read_mostly;
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#endif
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void __init x86_64_init_pda(void)
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{
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_cpu_pda = __cpu_pda;
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cpu_pda(0) = &_boot_cpu_pda;
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pda_init(0);
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}
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static void __init zap_identity_mappings(void)
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{
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pgd_t *pgd = pgd_offset_k(0UL);
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pgd_clear(pgd);
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__flush_tlb_all();
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}
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/* Don't add a printk in there. printk relies on the PDA which is not initialized
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yet. */
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static void __init clear_bss(void)
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{
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memset(__bss_start, 0,
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(unsigned long) __bss_stop - (unsigned long) __bss_start);
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}
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static void __init copy_bootdata(char *real_mode_data)
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{
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char * command_line;
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memcpy(&boot_params, real_mode_data, sizeof boot_params);
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if (boot_params.hdr.cmd_line_ptr) {
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command_line = __va(boot_params.hdr.cmd_line_ptr);
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memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
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}
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}
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void __init x86_64_start_kernel(char * real_mode_data)
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{
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int i;
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/*
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* Build-time sanity checks on the kernel image and module
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* area mappings. (these are purely build-time and produce no code)
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*/
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BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
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BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
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BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
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BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
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BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
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BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
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BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
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(__START_KERNEL & PGDIR_MASK)));
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BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
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/* clear bss before set_intr_gate with early_idt_handler */
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clear_bss();
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/* Make NULL pointers segfault */
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zap_identity_mappings();
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/* Cleanup the over mapped high alias */
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cleanup_highmap();
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for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
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#ifdef CONFIG_EARLY_PRINTK
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set_intr_gate(i, &early_idt_handlers[i]);
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#else
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set_intr_gate(i, early_idt_handler);
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#endif
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}
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load_idt((const struct desc_ptr *)&idt_descr);
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if (console_loglevel == 10)
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early_printk("Kernel alive\n");
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x86_64_init_pda();
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x86_64_start_reservations(real_mode_data);
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}
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void __init x86_64_start_reservations(char *real_mode_data)
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{
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copy_bootdata(__va(real_mode_data));
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reserve_trampoline_memory();
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reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
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#ifdef CONFIG_BLK_DEV_INITRD
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/* Reserve INITRD */
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if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
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unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
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unsigned long ramdisk_size = boot_params.hdr.ramdisk_size;
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unsigned long ramdisk_end = ramdisk_image + ramdisk_size;
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reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
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}
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#endif
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reserve_ebda_region();
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/*
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* At this point everything still needed from the boot loader
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* or BIOS or kernel text should be early reserved or marked not
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* RAM in e820. All other memory is free game.
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*/
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start_kernel();
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}
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